1. Field of the Invention
This invention relates to a press-contact type semiconductor device and, more particularly, to a press-contact type semiconductor device with a low ON voltage for turning on the elements incorporated therein.
2. Description of the Related Art
In an ordinary press-contact type semiconductor device, an electrode which is formed on the semiconductor pellet (this electrode is hereinafter referred to as the pellet electrode), and an electrode with which the device package is provided (this electrode is hereinafter referred to as the external electrode), are brought into pressure-contact with each other so as to achieve electrical connection therebetween. The contacts of the pellet electrode and the external electrode can resist a high voltage, and consequently the above semiconductor device is commonly used as a semiconductor device to which a large current is supplied.
In general, in a press-contact type semiconductor device to which a large current is supplied, a stress decreasing member (hereinafter referred to as the soft-metal plate) constituted by a relatively soft metal (e.g. copper) sheet is inserted between the pellet electrode and the external electrode in order to prevent the pellet from cracking due to stress resulting from generation of heat.
However, such a semiconductor device has the drawback that the resistance between the pellet electrode and the external electrode is high due to the insulating film covering the pellet electrode, resulting in a high ON voltage for turning on the elements incorporated in the semiconductor device.